The long-term objective of this proposal is to develop a safe and effective technique to deliver ATP directly to the human body and by-pass the body's need for oxygen. All cells of the body require oxygen and nutrients in order to make energy, and the energy is used to maintain homeostasis. Adenosine triphosphate (ATP) is the immediate source of energy that is constantly synthesized and metabolized in the body to maintain life. Without oxygen, ATP cannot be synthesized effectively in large quantities and thus the cells will die quickly from lack of energy and loss of homeostasis. Unfortunately many life-threatening conditions, such as heart attack, stroke, spinal cord injury, chronic obstructive pulmonary disease, and many surgical procedures all involve ischemia or hypoxia (low oxygen), which can cause reduced cellular energy and cell death. Over the years many attempts at restoring cellular energy have been unsuccessful, including direct intravenous infusion of ATP during ischemia. The major problem is that highly charged energetic phosphates, like ATP, do not pass through cell membranes and cannot be used for cell metabolism. The investigators have developed a new technique that delivers ATP and other high energy phosphates directly to cells, thus by-passing the need for oxygen. Our preliminary results indicate that our technique for delivering ATP can equal or supercede the cells need for ATP. Using this technique in a rat hindlimb preservation and transplantation model at room temperature, they can extend the preservation time of the severed limb to more than 20 hours, which is over 14 hours longer than previous attempts. This same technique has also been used by our company to extend heart preservation, and organism preservation. This Phase I proposal will further confirm our research concept and improve the effectiveness of our ATP delivery system. The aims are to: 1) further characterize the ATP delivery technique to improve the properties of the delivery vehicle (composition, dosage, temperature, concentration, and so on) to match the metabolic demand of different cell types; 2) study the cellular effect of this delivery technique in order to assess its toxic effects on cells; 3) study the method to deliver ATP not only to endothelial cells, but also to the cells outside of the vasculature by creating suitable gaps between endothelial cells; 4) to test the new ATP delivery technique in a composite tissue. The success of this project will have a huge impact on medicine and could change treatment strategies in many medical and surgical ischemic conditions.